feat(tui): add process features watch and kill

README.md

@@ -73,6 +73,9 @@ g/G           top/bottom
 t/u           toggle tcp/udp
 l/e/o         toggle listen/established/other
 s/S           cycle sort / reverse
+w             watch/monitor process (highlight)
+W             clear all watched
+K             kill process (with confirmation)
 /             search
 enter         connection details
 ?             help

internal/tui/keys.go

@@ -1,7 +1,9 @@
 package tui
 
 import (
+	"fmt"
 	"snitch/internal/collector"
+	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
 )
@@ -12,6 +14,11 @@ func (m model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		return m.handleSearchKey(msg)
 	}
 
+	// kill confirmation dialog
+	if m.showKillConfirm {
+		return m.handleKillConfirmKey(msg)
+	}
+
 	// detail view only allows closing
 	if m.showDetail {
 		return m.handleDetailKey(msg)
@@ -62,6 +69,25 @@ func (m model) handleHelpKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+func (m model) handleKillConfirmKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
+	switch msg.String() {
+	case "y", "Y":
+		if m.killTarget != nil && m.killTarget.PID > 0 {
+			pid := m.killTarget.PID
+			process := m.killTarget.Process
+			m.showKillConfirm = false
+			m.killTarget = nil
+			return m, killProcess(pid, process)
+		}
+		m.showKillConfirm = false
+		m.killTarget = nil
+	case "n", "N", "esc", "q":
+		m.showKillConfirm = false
+		m.killTarget = nil
+	}
+	return m, nil
+}
+
 func (m model) handleNormalKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	switch msg.String() {
 	case "q", "ctrl+c":
@@ -135,6 +161,55 @@ func (m model) handleNormalKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		return m, m.fetchData()
 	case "?":
 		m.showHelp = true
+
+	// watch/monitor process
+	case "w":
+		visible := m.visibleConnections()
+		if m.cursor < len(visible) {
+			conn := visible[m.cursor]
+			if conn.PID > 0 {
+				wasWatched := m.isWatched(conn.PID)
+				m.toggleWatch(conn.PID)
+
+				// count connections for this pid
+				connCount := 0
+				for _, c := range m.connections {
+					if c.PID == conn.PID {
+						connCount++
+					}
+				}
+
+				if wasWatched {
+					m.statusMessage = fmt.Sprintf("unwatched %s (pid %d)", conn.Process, conn.PID)
+				} else if connCount > 1 {
+					m.statusMessage = fmt.Sprintf("watching %s (pid %d) - %d connections", conn.Process, conn.PID, connCount)
+				} else {
+					m.statusMessage = fmt.Sprintf("watching %s (pid %d)", conn.Process, conn.PID)
+				}
+				m.statusExpiry = time.Now().Add(2 * time.Second)
+				return m, clearStatusAfter(2 * time.Second)
+			}
+		}
+	case "W":
+		// clear all watched
+		count := len(m.watchedPIDs)
+		m.watchedPIDs = make(map[int]bool)
+		if count > 0 {
+			m.statusMessage = fmt.Sprintf("cleared %d watched processes", count)
+			m.statusExpiry = time.Now().Add(2 * time.Second)
+			return m, clearStatusAfter(2 * time.Second)
+		}
+
+	// kill process
+	case "K":
+		visible := m.visibleConnections()
+		if m.cursor < len(visible) {
+			conn := visible[m.cursor]
+			if conn.PID > 0 {
+				m.killTarget = &conn
+				m.showKillConfirm = true
+			}
+		}
 	}
 
 	return m, nil

internal/tui/messages.go

@@ -1,7 +1,9 @@
 package tui
 
 import (
+	"fmt"
 	"snitch/internal/collector"
+	"syscall"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -17,6 +19,15 @@ type errMsg struct {
 	err error
 }
 
+type killResultMsg struct {
+	pid     int
+	process string
+	success bool
+	err     error
+}
+
+type clearStatusMsg struct{}
+
 func (m model) tick() tea.Cmd {
 	return tea.Tick(m.interval, func(t time.Time) tea.Msg {
 		return tickMsg(t)
@@ -33,3 +44,40 @@ func (m model) fetchData() tea.Cmd {
 	}
 }
 
+func killProcess(pid int, process string) tea.Cmd {
+	return func() tea.Msg {
+		if pid <= 0 {
+			return killResultMsg{
+				pid:     pid,
+				process: process,
+				success: false,
+				err:     fmt.Errorf("invalid pid"),
+			}
+		}
+
+		// send SIGTERM first (graceful shutdown)
+		err := syscall.Kill(pid, syscall.SIGTERM)
+		if err != nil {
+			return killResultMsg{
+				pid:     pid,
+				process: process,
+				success: false,
+				err:     err,
+			}
+		}
+
+		return killResultMsg{
+			pid:     pid,
+			process: process,
+			success: true,
+			err:     nil,
+		}
+	}
+}
+
+func clearStatusAfter(d time.Duration) tea.Cmd {
+	return tea.Tick(d, func(t time.Time) tea.Msg {
+		return clearStatusMsg{}
+	})
+}
+

internal/tui/model.go

@@ -1,6 +1,7 @@
 package tui
 
 import (
+	"fmt"
 	"snitch/internal/collector"
 	"snitch/internal/theme"
 	"time"
@@ -35,6 +36,17 @@ type model struct {
 	interval    time.Duration
 	lastRefresh time.Time
 	err         error
+
+	// watched processes
+	watchedPIDs map[int]bool
+
+	// kill confirmation
+	showKillConfirm bool
+	killTarget      *collector.Connection
+
+	// status message (temporary feedback)
+	statusMessage string
+	statusExpiry  time.Time
 }
 
 type Options struct {
@@ -93,6 +105,7 @@ func New(opts Options) model {
 		theme:           theme.GetTheme(opts.Theme),
 		interval:        interval,
 		lastRefresh:     time.Now(),
+		watchedPIDs:     make(map[int]bool),
 	}
 }
 
@@ -127,6 +140,21 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case errMsg:
 		m.err = msg.err
 		return m, nil
+
+	case killResultMsg:
+		if msg.success {
+			m.statusMessage = fmt.Sprintf("killed %s (pid %d)", msg.process, msg.pid)
+		} else {
+			m.statusMessage = fmt.Sprintf("failed to kill pid %d: %v", msg.pid, msg.err)
+		}
+		m.statusExpiry = time.Now().Add(3 * time.Second)
+		return m, tea.Batch(m.fetchData(), clearStatusAfter(3*time.Second))
+
+	case clearStatusMsg:
+		if time.Now().After(m.statusExpiry) {
+			m.statusMessage = ""
+		}
+		return m, nil
 	}
 
 	return m, nil
@@ -142,7 +170,15 @@ func (m model) View() string {
 	if m.showDetail && m.selected != nil {
 		return m.renderDetail()
 	}
-	return m.renderMain()
+
+	main := m.renderMain()
+
+	// overlay kill confirmation modal on top of main view
+	if m.showKillConfirm && m.killTarget != nil {
+		return m.overlayModal(main, m.renderKillModal())
+	}
+
+	return main
 }
 
 func (m *model) applySorting() {
@@ -167,7 +203,8 @@ func (m *model) clampCursor() {
 }
 
 func (m model) visibleConnections() []collector.Connection {
-	var result []collector.Connection
+	var watched []collector.Connection
+	var unwatched []collector.Connection
 
 	for _, c := range m.connections {
 		if !m.matchesFilters(c) {
@@ -176,10 +213,15 @@ func (m model) visibleConnections() []collector.Connection {
 		if m.searchQuery != "" && !m.matchesSearch(c) {
 			continue
 		}
-		result = append(result, c)
+		if m.isWatched(c.PID) {
+			watched = append(watched, c)
+		} else {
+			unwatched = append(unwatched, c)
+		}
 	}
 
-	return result
+	// watched connections appear first
+	return append(watched, unwatched...)
 }
 
 func (m model) matchesFilters(c collector.Connection) bool {
@@ -218,3 +260,25 @@ func (m model) matchesSearch(c collector.Connection) bool {
 		containsIgnoreCase(c.Proto, m.searchQuery) ||
 		containsIgnoreCase(c.State, m.searchQuery)
 }
+
+func (m model) isWatched(pid int) bool {
+	if pid <= 0 {
+		return false
+	}
+	return m.watchedPIDs[pid]
+}
+
+func (m *model) toggleWatch(pid int) {
+	if pid <= 0 {
+		return
+	}
+	if m.watchedPIDs[pid] {
+		delete(m.watchedPIDs, pid)
+	} else {
+		m.watchedPIDs[pid] = true
+	}
+}
+
+func (m model) watchedCount() int {
+	return len(m.watchedPIDs)
+}

internal/tui/view.go

@@ -158,6 +158,8 @@ func (m model) renderRow(c collector.Connection, selected bool) string {
 	indicator := "  "
 	if selected {
 		indicator = m.theme.Styles.Success.Render("▸ ")
+	} else if m.isWatched(c.PID) {
+		indicator = m.theme.Styles.Watched.Render("★ ")
 	}
 
 	process := truncate(c.Process, cols.process)
@@ -200,7 +202,18 @@ func (m model) renderRow(c collector.Connection, selected bool) string {
 }
 
 func (m model) renderStatusLine() string {
-	left := "  " + m.theme.Styles.Normal.Render("t/u proto  l/e/o state  s sort  / search  ? help  q quit")
+	// show status message if present
+	if m.statusMessage != "" {
+		return "  " + m.theme.Styles.Warning.Render(m.statusMessage)
+	}
+
+	left := "  " + m.theme.Styles.Normal.Render("t/u proto  l/e/o state  w watch  K kill  s sort  / search  ? help  q quit")
+
+	// show watched count if any
+	if m.watchedCount() > 0 {
+		watchedInfo := fmt.Sprintf("  watching: %d", m.watchedCount())
+		left += m.theme.Styles.Watched.Render(watchedInfo)
+	}
 
 	return left
 }
@@ -233,6 +246,12 @@ func (m model) renderHelp() string {
   s            cycle sort field
   S            reverse sort order
 
+  process management
+  ──────────────────
+  w            watch/unwatch process (highlight & track)
+  W            clear all watched processes
+  K            kill process (with confirmation)
+
   other
   ─────
   /            search
@@ -286,6 +305,183 @@ func (m model) renderDetail() string {
 	return b.String()
 }
 
+func (m model) renderKillModal() string {
+	if m.killTarget == nil {
+		return ""
+	}
+
+	c := m.killTarget
+	processName := c.Process
+	if processName == "" {
+		processName = "(unknown)"
+	}
+
+	// count how many connections this process has
+	connCount := 0
+	for _, conn := range m.connections {
+		if conn.PID == c.PID {
+			connCount++
+		}
+	}
+
+	// build modal content
+	var lines []string
+	lines = append(lines, "")
+	lines = append(lines, m.theme.Styles.Error.Render("  !!  KILL PROCESS?  "))
+	lines = append(lines, "")
+	lines = append(lines, fmt.Sprintf("  process:  %s", m.theme.Styles.Header.Render(processName)))
+	lines = append(lines, fmt.Sprintf("  pid:      %s", m.theme.Styles.Header.Render(fmt.Sprintf("%d", c.PID))))
+	lines = append(lines, fmt.Sprintf("  user:     %s", c.User))
+	lines = append(lines, fmt.Sprintf("  conns:    %d", connCount))
+	lines = append(lines, "")
+	lines = append(lines, m.theme.Styles.Warning.Render("  sends SIGTERM to process"))
+	if connCount > 1 {
+		lines = append(lines, m.theme.Styles.Warning.Render(fmt.Sprintf("  will close all %d connections", connCount)))
+	}
+	lines = append(lines, "")
+	lines = append(lines, fmt.Sprintf("  %s confirm   %s cancel",
+		m.theme.Styles.Success.Render("[y]"),
+		m.theme.Styles.Error.Render("[n]")))
+	lines = append(lines, "")
+
+	return strings.Join(lines, "\n")
+}
+
+func (m model) overlayModal(background, modal string) string {
+	bgLines := strings.Split(background, "\n")
+	modalLines := strings.Split(modal, "\n")
+
+	// find max modal line width using runewidth for proper unicode handling
+	modalWidth := 0
+	for _, line := range modalLines {
+		w := runeWidth(stripAnsi(line))
+		if w > modalWidth {
+			modalWidth = w
+		}
+	}
+	modalWidth += 4 // padding for box
+
+	modalHeight := len(modalLines)
+	boxWidth := modalWidth + 2 // include border chars │ │
+
+	// calculate modal position (centered)
+	startRow := (m.height - modalHeight) / 2
+	if startRow < 2 {
+		startRow = 2
+	}
+	startCol := (m.width - boxWidth) / 2
+	if startCol < 0 {
+		startCol = 0
+	}
+
+	// build result
+	result := make([]string, len(bgLines))
+	copy(result, bgLines)
+
+	// ensure we have enough lines
+	for len(result) < startRow+modalHeight+2 {
+		result = append(result, strings.Repeat(" ", m.width))
+	}
+
+	// helper to build a line with modal overlay
+	buildLine := func(bgLine, modalContent string) string {
+		modalVisibleWidth := runeWidth(stripAnsi(modalContent))
+		endCol := startCol + modalVisibleWidth
+
+		leftBg := visibleSubstring(bgLine, 0, startCol)
+		rightBg := visibleSubstring(bgLine, endCol, m.width)
+
+		// pad left side if needed
+		leftLen := runeWidth(stripAnsi(leftBg))
+		if leftLen < startCol {
+			leftBg = leftBg + strings.Repeat(" ", startCol-leftLen)
+		}
+
+		return leftBg + modalContent + rightBg
+	}
+
+	// draw top border
+	borderRow := startRow - 1
+	if borderRow >= 0 && borderRow < len(result) {
+		border := m.theme.Styles.Border.Render("╭" + strings.Repeat("─", modalWidth) + "╮")
+		result[borderRow] = buildLine(result[borderRow], border)
+	}
+
+	// draw modal content with side borders
+	for i, line := range modalLines {
+		row := startRow + i
+		if row >= 0 && row < len(result) {
+			content := line
+			padding := modalWidth - runeWidth(stripAnsi(line))
+			if padding > 0 {
+				content = line + strings.Repeat(" ", padding)
+			}
+			boxedLine := m.theme.Styles.Border.Render("│") + content + m.theme.Styles.Border.Render("│")
+			result[row] = buildLine(result[row], boxedLine)
+		}
+	}
+
+	// draw bottom border
+	bottomRow := startRow + modalHeight
+	if bottomRow >= 0 && bottomRow < len(result) {
+		border := m.theme.Styles.Border.Render("╰" + strings.Repeat("─", modalWidth) + "╯")
+		result[bottomRow] = buildLine(result[bottomRow], border)
+	}
+
+	return strings.Join(result, "\n")
+}
+
+// runeWidth returns the display width of a string (assumes standard terminal chars)
+func runeWidth(s string) int {
+	return len([]rune(s))
+}
+
+// visibleSubstring extracts a substring by visible column positions, preserving ANSI codes
+func visibleSubstring(s string, start, end int) string {
+	if start >= end {
+		return ""
+	}
+
+	var result strings.Builder
+	visiblePos := 0
+	inEscape := false
+	runes := []rune(s)
+
+	for i := 0; i < len(runes); i++ {
+		r := runes[i]
+
+		// detect start of ANSI escape sequence
+		if r == '\x1b' && i+1 < len(runes) && runes[i+1] == '[' {
+			inEscape = true
+			// always include ANSI codes so colors carry over
+			result.WriteRune(r)
+			continue
+		}
+
+		if inEscape {
+			// include escape sequence characters
+			result.WriteRune(r)
+			// check for end of escape sequence (letter)
+			if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') {
+				inEscape = false
+			}
+			continue
+		}
+
+		// regular visible character
+		if visiblePos >= start && visiblePos < end {
+			result.WriteRune(r)
+		}
+		visiblePos++
+
+		if visiblePos >= end {
+			break
+		}
+	}
+
+	return result.String()
+}
+
 func (m model) scrollOffset(pageSize, total int) int {
 	if total <= pageSize {
 		return 0